1. Field of the Invention
The invention relates to transformers having amorphous metal cores, and particularly to such transformers having wound rectangular cores.
2. Description of the Prior Art
Despite its high cost, amorphous metal is gradually replacing electrical grade steel in transformer cores because it is a lower loss material than with regular grain oriented electrical steel. A wound core transformer can be made from amorphous metal by winding an amorphous metal sheet into a core over a two-piece inside mandrel or core support, cutting one leg of the core, and forming the metal into a generally rectangular shape. Magnetic cores wound from a strip of amorphous metal are not self-supporting and will collapse if not otherwise supported if the mold portion of the winding mandrel is removed from the core window. If an amorphous core is not operated in the as annealed configuration the core losses increase. The amorphous metal is annealed, which converts it into a very brittle material. Annealing optimizes the magnetic characteristics of the core. However, after annealing slivers and flakes of the amorphous metal may contaminate the liquid coolant.
There is a need for a high volume method of producing cores while resisting the presence of contaminants in the transformer coolant.
There remains a need for an economical high volume method of producing a self-supporting amorphous metal transformer.